When laundry is washed in a washer, it is common to add a treatment substance to water, in particular, to rinsing water. Typical examples of such treatment substances include softening and starching agents. In addition to these, in recent years, the demand has been increasing for treatment whereby laundry is subjected to antimicrobial treatment.
From the hygienic point of view, it is desirable to hang laundry in the sun to dry. However, in recent years, with the increase in the number of women who go to work, and with the increase in the number of nuclear families, there have been an increasing number of households where no one is at home in the daytime. In these households, there is no choice but to hang laundry indoors to dry. Even in households where someone is at home in the daytime, in a rainy weather, there is no choice but to hang laundry indoors to dry.
As compared with hanging laundry in the sun to dry, hanging it indoors tends to promote growth of bacteria and mold in laundry. This tendency is marked particularly when it takes time to dry laundry, as when humidity is high, such as in a rainy season, or when temperature is low. As the amount of bacteria and mold increases, laundry may become smelly. For this reason, in households where there is usually no choice but to hang laundry indoors to dry, there is a high demand for antimicrobial treatment of textile articles for the purpose of suppressing growth of bacteria and mold.
Nowadays, many clothes are available that have previously been treated with antimicrobial/deodorizing or antifungal treatment. However, it is difficult to replace all the textile articles in a household with those previously treated with antimicrobial/deodorizing treatment. Moreover, even with such textile articles, as they are washed repeatedly, the efficacy of antimicrobial/deodorizing treatment wears off.
Conceived under these circumstances was the idea of treating laundry with antimicrobial treatment every time it is washed. For example, Japanese Utility Model Laid-Open No. H5-74487 discloses an electric washer furnished with an ion generator that generates metal ions, such as silver ions or copper ions that exert a sterilizing effect. Japanese Patent Application Laid-Open No. 2000-93691 discloses a washer that generates an electric field with which to sterilize cleaning fluid. Japanese Patent Application Laid-Open No. 2001-276484 discloses a washer furnished with a silver ion adding unit that adds silver ions to cleaning water.